Process for eliminating smell defects and/or off-flavors in fermented or non-fermented fruit juices, in particular wine, fruit wine or fruit distillate products

ABSTRACT

To eliminate from non-fermented or fermented fruit juices obtained from fruit or grapes, in particular wine, the undesirable odors and/or taste caused by sulphur or sulphur compounds, called &#34;Bockser&#34;, it is proposed according to the invention to add hardly soluble or insoluble organic Cu-compounds to the liquid, which, by reacting with the sulphur or sulphur compounds, form insoluble sulphides that can easily be separated from the liquid by precipitation. Particularly suitable for this are copper salts of citric acid, tartaric acid, malic acid or stearic acid or mixtures of these salts.

This is a National Stage application under 35 USC 371 of PCT/EP96/02056filed May 14, 1996.

BACKGROUND OF THE INVENTION

1. The Technical Field

The invention relates to a process for eliminating from non-fermented orfermented fruit juices obtained from fruit or grapes, in particularwine, fruit wine or fruit distillates, undesirable odors and/or tasteswhich are caused by the formation of sulphur compounds, in particularhydrogen sulphide.

2. The Prior Art

During the reductive fermenting of fruit juices, hydrogen sulphide andother sulphur compounds occur. The resultant adverse effect on the aromaand taste of the fermentation products, called "Bockser" ("Bockser"=theGerman term for the unpleasant odor and taste caused by hydrogensulphide), is unpleasant and persistent.

Various treatment methods and cellar measures are known to remove the"Bockser", such as adsorption on bentonites or activated charcoal,aeration, filtration. However, these processes have the disadvantagethat their use has a considerable adverse effect on the quality of thewine.

Also known is the use of copper sulphate, which is allowed as a foodadditive, to remove the "Bockser". The excess copper must then beremoved by precipitation with potassium hexacyanoferrate-II. Such atreatment is environmentally harmful, extremely labor intensive andoutmoded.

To remove the "Bockser", it is also known to mix the fermentationproducts with electrolytically precipitated metal ions, preferablyAg-ions which, with the substances in the liquid that cause theundesirable odors and taste, form insoluble salts. This method, known asthe catadyn process, results in harmful Ag-ions in the wine. Thisprocess is at best suitable for alcohol distillates.

It is the object of the invention to eliminate the aforementioneddisadvantages that occur during the removal of the "Bockser" and toindicate an environmentally friendly process.

DETAILED DISCLOSURE OF THE INVENTION

According to the invention this object is addressed by thecharacterizing features of claim 1 in that organic Cu-compounds areadded to the fruit juices, wine, fruit wine or fruit distillates, whichCu-compounds are hardly soluble or insoluble in water as well as innon-fermented and fermented fruit juices, wine, fruit wine or fruitdistillates and which, by reacting with the sulphur compounds, forminsoluble sulphides that are separated from the liquid by precipitation.The insoluble sulphides formed when organic copper compounds react withthe to be removed sulphur compounds can easily be separated from thewine, fruit wine, fruit distillates or fruit juices as insoluble solids.

Hardly soluble or insoluble copper salts of citric acid, tartaric acid,malic acid, stearic acid or lactic acid, which have the advantage thatthey are suitable food additives and not harmful from an ecologicalpoint of view, have proved particularly suitable for the processaccording to the invention.

Preferably, copper salts of monovalent or multivalent carboxylic acids,e.g. copper stearate, copper citrate, copper malate, copper tartrate,copper lactate are used, which react with the sulphur compounds to forminsoluble copper sulphide.

Also mixtures of the above-mentioned salts can be used with the sameadvantage. A particularly good efficacy is obtained when the coppercompounds are used in combination with adsorption agents or filter aids,in which connection bentonites are particularly suitable as adsorptionagents. They have a high swelling ability and good ion exchange abilityand serve to agglomerate the copper compounds.

The crushed bentonite compound can be impregnated with soluble coppersalts and then be acted upon with carboxylic acids to form the insolublecarboxylate.

For the implementation of the process according to the invention it isadvantageous to mix granulates of aqueous suspensions of bentonite withcopper carboxylates that are obtained, for example, by spray drying.

Also activated charcoal, possibly combined with bentonite, can be usedas adsorption agent.

In the following the invention will be described with reference to anexample: 5 g of pure copper citrate are mixed with 95 g bentonite. Thegranulated mixture is introduced into 1000 l wine contaminated with"Bockser" and stirred for about 2 hours. After the precipitation thewine is siphoned off and filtered. The organoleptic test showed aperfect drinking quality of the previously undrinkable wine.

We claim:
 1. A process for the elimination, through addition of Cucompounds, of undesirable odors and tastes from non-fermented orfermented fruit juices obtained from fruit or grapes, the cause of whichlies in the formation of sulfur compounds, characterized in that one ormore organic Cu compounds, which are hardly soluble or insoluble inwater, as well as in non-fermented and fermented fruit juices, wine,fruit wine, or fruit distillates, are added to the non-fermented orfermented fruit juices, wine, fruit wine, or fruit distillates, andwhich, by reacting with the sulfur compounds in said non-fermented orfermented fruit juices, wine, fruit wine, or fruit distillates,insoluble sulfides are formed which are then separated from thenon-fermented or fermented fruit juice, wine, fruit wine, or fruitdistillate, by precipitation, wherein the Cu compounds used are hardlysoluble or insoluble copper salts of monovalent or multivalentcarboxylic acids.
 2. A process according to claim 1, characterized inthat the one or more Cu compounds used comprise one or more monovalentor multivalent copper salts, from the group consisting of copperstearate, copper citrate, copper malate, copper tartrate, copperlactate, mixtures of these salts.
 3. A process according to claim 1,characterized in that the Cu compounds are used together with absorptionagents.
 4. A process according to claim 3, characterized in thatbentonite, which is used as a granulate, is mixed with copper salts andis then exposed to carboxylic acids.
 5. A process for eliminatingundesirable odors and off-flavours from a liquid selected from the groupconsisting of non-fermented and fermented fruit juices from fruits andfrom grapes, wine, fruit wine and fruit distillates, wherein the causeof said odors and off-flavours lies in the formation of Bockser, whereinone or more organic Cu-compounds which are hardly soluble or insolublein water and in non-fermented fruit juices, fermented fruit juices,wine, fruit wine and fruit distillates, are added to said liquid forforming insoluble sulfides, and wherein said insoluble sulfides areseparated from said liquid by precipitation.
 6. A process foreliminating undesirable odors and off-flavours from a liquid selectedfrom the group consisting of non-fermented and fermented fruit juicesfrom fruits and from grades, wine, fruit wine and fruit distillates,wherein the cause of said odors and off-flavours lines in the formationof Bockser, wherein one or more organic Cu-compounds which are hardlysoluble or insoluble in water and in non-fermented fruit juices,fermented fruit juices, wine, fruit wine and fruit distillates, areadded to said liquid for forming insoluble sulfides, and wherein saidinsoluble sulfides are separated from said liquid by precipitation, saidorganic Cu-compounds are selected from the group consisting of coppersalts of carboxylic acids.
 7. A process according to claim 6, whereinsaid copper salt of carboxylic acid is selected from the groupconsisting of copper stearate, copper citrate, copper malate, coppertartrate, copper lactate and mixtures thereof.
 8. A process according toclaim 6, wherein said organic Cu-compound is used together with anabsorption agent.
 9. A process according to claim 6, wherein saidCu-compound is used together with an absorption agent.
 10. A processaccording to claim 9, wherein said absorption agent is bentonite.
 11. Aprocess according to claim 10, wherein said bentonite is used as agranulate and wherein said granulate is impregnated with a solublecopper salt and exposed to a carboxylic acid.
 12. A process according toclaim 3, wherein said absorption agent is bentonite.
 13. A processaccording to claim 5, wherein said organic Cu-compounds are selectedfrom the group consisting of copper salts of carboxylic acids.
 14. Aprocess according to claim 13, wherein said copper salt of carboxylicacid is selected from the group consisting of copper stearate, coppercitrate, copper malate, copper tartrate, copper lactate and mixturesthereof.
 15. A process according to claim 5, wherein said organicCu-compound is used together with an absorption agent.
 16. A processaccording to claim 13, wherein said Cu-compound is used together with anabsorption agent.
 17. A process according to claim 16, wherein saidabsorption agent is bentonite.
 18. A process according to claim 17,wherein said bentonite is used as a granulate and wherein said granulateis impregnated with a soluble copper salt and exposed to a carboxylicacid.